Apparatus for testing oil and gas wells



Feb. 13, 1940. g. E. BLACKBURN 2,190,250

APPARATUS FOR TESTING OIL AND GAS WELLS Filed Oct. 18, 1937 INVENTOR.

Patented Feb. 13, 1940 UNITED STATES APPARATUS FOR, TESTING OIL AND GAS WELLS Claude Earl Blackburn, Burger, Tex., assignor to J. M. Huber Corporation, Burger, Tex., a corporation of Delaware Application October 18, 1937, Serial No. 169,684

3 Claims.

This invention pertains to testing wells where gas or oil formations are encountered or are expected to have been encountered, and is an apparatus by which without cementing a string of 6 casing, a formation test can be made for any period of time without danger of sticking the drill pipe, as circulation is maintained throughout the test.

It frequently happens when formation tests are made by apparatus now in use that the drill stem is stuck, as in such apparatus the drill pipe is run in the hole with a formation tester on the bottom, which is set on a shoulder for a formation shut-off, and the well is produced through the drill stem for the test. This fault of sticking of the drill stem is caused by formations above the tester caving off on the tester or cuttings in the drilling and settling around the drill pipe. Formation tests are usually continued for only a short period of time because of the possibility of sticking of the drill pipe, which may result in a lengthy and costly fishing job, and possibly the abandonment of the hole:

It is therefore the primary object of this invention to make is possible to avoid the hazard or possibility of the sticking of the drill pipe during the formation test, and to thus enable the operator to continue the test on the formation for any duration of time he deems necessary to thoroughly test the formation and to secure an accurate estimate of how much the well will produce.

The invention will be clearly understood from a perusal of the following detailed description, taken in connection with the drawing and in the drawing: 1

Figure 1 represents an elevational view of a rotary table and adjacent parts, with a circulating and packing head, which may be employed with the apparatus on which a patent is sought,

Figure 2 is a vertical or longitudinal sectional view of a tester to be used on the drill pipe as emplayed in the invention, and

In the apparatus herein carried out and as shown in Figure 2, the formation has been cored with a smaller diameter hole than the drill hole. as is the custom, which has left a shoulder as referred to upon which the packer element 2 has been seated. The mud, entering through the openings 6 in the packing and circulating head is circulated, as indicated by the arrows, between the inner string 1 and the drill pipe or casing 8, thence out through the packer element 2, which constitutes part of the tester as a whole, through the openings 9. -These openings communicate with a chamber In formed in the packer element 2, as will be apparent from Figure 3. The openings 9 may be in the form of slots or holes, and the mud after passing through these openings is carried to a mud pit, being delivered thereto through the outlet H.

At the lower end of the packer element 2, is a perforated member l2 with the spaced openings l3, this member being threadedly engaged with the packer element and having open communication by means of a bore or channel M with the inner string 1. The oil or gas enters the perforations in the member I2, then passes along the bore M to the inner string 1 to the surface. The

oil or gas is prevented from leaking into the mud stream at the point where the bottom of the inner string 1 joins the upper end of the bore i l by means'of a ground joint and a lead seat IS on the inner string, in addition to the rubber packing ring It. The bottom of the inner string is securely held in place by the weight of the inner string itself. The lower end of the inner string and the packing ring it are both beveled as shown in Figure 2, and the ring provides an additional factor of safety to prevent a leak into the mud stream. Finally a steel ring I! is placed on the packing ring I 6 to deflect the flow of mud from the ring l6.

The mud enters, as shown in Figure 1, through the openings 6. A Christmas tree is placed on the swage nipple 20 and lines are laid from this to the tanks or other receptacles. A rotary table is indicated at 200 and blow-out preventers at 22.

From the foregoing it will be apparent that the circulation of the mud stream is between the inner string 1 and the drill pipe 8 on its downward flow and that after passing into the chamber l0 and into the openings or mud ducts 9 the upward flow will be between the drill pipe and the walls of the hole or casing thereof. This arrangement as carried out in the invention provides for the prevention of all cuttings and cavings from settling around the tester and thus insures the safety of the drill stem or casing while the test is being carried out. In order to start the flow of oil or gas through the inner string, it maybe necessary to swab some of the fluid out of .it. Of if a mechanical foot valve is used, it is opened by letting down the inner string and the well will flow up into the empty inner string. The flow of oil or gas through the inner string into tanks or other suitable receptacles may be continued as long as necessary to thoroughly test the formation, as during the entire test the circulation is carried on, keeping the drill pipe free from sticking. At the conclusion of the test the control valve on the top of the inner string is closed to shut oif the flow of oil or gas and mud is pumped down into the inner string and into the formation to mud it off again. The inner string is then pulled while circulation is continued as in running the inner string into the hole. When the inner string has been drawn out of the hole, the packing and circulating head is removed and the drill pipe is removed or pulled.

While the disclosure embodies a practical working embodiment of the invention, it is to be understood that modifications and alterations are possible and the invention includes the structure disclosed including such changes as might be said to fall fairly within the scope and meaning of the claims appended hereto.

What is claimed as new is:

1. A formation tester for oil and gas wells for determining production, comprising in combination with the drill pipe of a packer'or shut-off element, a perforated tube attached to the lower end of the packer element for gas and oil entrance, said packer element being centrally bored and having a chamber with outlet ducts for a mud stream flow, said drill pipe being connected to and having open communication with said chamber, a pipe string disposed within the drill pipe for oil and gas flow extending through the said chamber of the packer element and having open communicationwith the packer element bore and with said perforated tube, said tester including means for sealing off the packer bore junction with the lower end of the inner pipe string against oil and gas leakage.

2. A formation tester for oil-and gas wells for determining production, comprising in combination with a drill pipe of a packer or shut-off element, a perforated tube attached to the lower end of the packer element for gas and oil entrance, said packer element being centrally bored and having a chamber in the upper end thereof with outlet ducts for a mud stream flow, said drill pipe being connected to and having open communication with said chamber, a pipe string disposed within the drill pipe for oil and gas flow extending through said chamber of the packer element and having open communication with the packer element bore and with said perforated tube, said tester including means for sealing off the packer bore junction with the lower end of the inner pipe string against oil and gas leakage and for sealing off the chamber in the packer element from the lower end of the inner pipe string against mud stream leakage, the said sealing means comprising a seat member on the lower end of the inner pipe string, and a packing ring spaced around the inner string of pipe at the bottom of the chamber in the packer element.

3. A formation tester for oil and gas wells for determining production, comprising in combination with a drill pipe of a packer or shut-off element, a perforated tube attached to the lower end of the packer element for gas and oil en-- trance, said packer element being centrally bored and having a chamber in the upper end thereof with outlet ducts for a mud stream flow, said drill pipe being connected to and having open communication with said chamber; a pipe string disposed within the drill pipe for oil and gas flow extending through said chamber of the packer element and having open communication with packer element bore and with said perforated tube, said tester including means for sealing oi? the packer bore junction with the lower end of the inner pipe string against oil and gas leakage and for sealing the chamber in the packer element from the lower end of the inner string of pipe against mud stream leakage, the said sealing means comprisinga seat member on the lower end of the inner pipe string, a tapered packing ring spaced around the inner string of pipe at the bottom of the chamber in the packer element and a flat metallic packing ring abutting the upper side of the tapered packing ring.

CLAUDE EARL BLACKBURN. 

